The known equipment for the production of foam boards generally consists of a conveyor, either an inclined or horizontal table at one end of the conveyor, an application device located above the table, and a distribution device located downstream of the table. A roller or a rake is generally provided as the distribution device. If a lower facing is used, it may be guided over the table and must stay in contact at the break point between the table and the conveyor.
The facing may, however, also be guided from underneath the table. This option is especially utilized when using stiff or rigid facings. In this case, the inclined table is preferably coated with a layer of polytetrafluoroethylene or silicone to prevent the mixture from sticking to it. In principle, all equipment parts which come in contact with the reaction mixture or with the forming foam could be provided with such a coating. In production, however, the use of facings, particularly of paper facings, has proved to be safer and more useful.
The problem with such known equipment is that the reaction mixture applied to the table cannot be distributed in time over the entire width before the reaction starts. Due to the relatively longer flow length, the reaction mixture begins to foam at the sides, before it passes the levelling (or distribution) device. This causes irregular sides due to insufficient and irregular filling of the cross section and/or cellular striations are formed.
It is the purpose of the invention to improve the application of the mixture over the entire width so that a substantially perfect end product is produced, which has well-formed sides and homogeneous foam thickness.